Some medical instruments, such as guide wires and needles that are used to help insert catheters, are inserted and left in blood vessels, respiratory tracts, urinary tracts, and other body cavities and tissues. When these medical instruments are inserted, the surface of the medical instrument should easily slide in order to avoid injuring tissue membranes and causing inflammation, as well as to relieve any pain experienced by the patient receiving the treatment.
Therefore, some medical instruments are provided with lubricity, which may be provided by applying a silicone oil, glycerin, or the like to the surface, as an innovation for enhancing sliding and reducing friction resistance. These medical instruments can easily be manufactured by dipping the medical instrument in a solution containing silicone oil or the like, or by spraying silicone oil or the like, and therefore this technique is suitable for a broad range of medical instruments.
Furthermore, some medical instruments, such as catheters made of synthetic resin, have a film formed thereon by applying onto the base material surface a solution including a methyl vinyl ether maleic anhydride copolymer and a polyether block amide dissolved in an organic solvent. Such a film coating may demonstrate excellent lubricity when wet. When the medical instrument is inserted into a body cavity, tissue, or the like, the surface of the medical instrument is moistened by the moisture in the body. Furthermore, the portion of the surface of the medical instrument where a film is formed will demonstrate lubricity with a slippery feel, and thus the surface of the medical instrument will easily slide. Therefore, when the medical instrument is inserted into a body cavity or the like, the practitioner, such as a doctor, will be able to easily insert the medical instrument.
In some cases, for medical instruments that possess lubricity from a film formed of a silicone oil, glycerin, or the like, the film can easily be removed by rubbing the region with lubricity by hand. Thus, providing lubricity using these films may not be suitable for medical instruments that are required to have peeling resistance of the lubricity.
Furthermore, for base materials made of metals, including guide wires, the adhesion of the film towards metal is greatly reduced, and as a result the lubrication layer or film may peel off or elute into physiological saline solution, or the like, when used for a long period of time or when used multiple times, and thus the lubricity is reduced.
Medical instruments with lubricity that have excellent peel durability and anti-eluting properties, and that can demonstrate excellent lubricity when wet, over a long period of time, remain desirable.